STATE OF ILLINOIS OTTO KERNER, Governor DEPARTMENT OF REGISTRATION AND EDUCATION WILLIAM SYLVESTER WHITE, Director

Transcription

1 Circular 83 STATE OF ILLINOIS OTTO KERNER, Governor DEPARTMENT OF REGISTRATION AND EDUCATION WILLIAM SYLVESTER WHITE, Director OFFICE COPY Water-Level Decline and Purn page During I960 in Deep Wells in the Chicago Region, Illinois by R.T. SASMAN, T.A. PRICKETT, and R.R. RUSSELL ILLINOIS STATE WATER SURVEY WILLIAM C. ACKERMANN, Chief URBANA 1961 Printed by authority of the State of Illinois

2 CONTENTS Summary... 3 Introduction...4 Geology and hydrology of Cambrian-Ordovician Aquifer... 6 Page Pumpage from deep well... 8 Pumpage in Practical sustained yield of Cambrian-Ordovician Aquifer in relation to pumpage in Water levels in deep wells...15 Water-level decline, October 1959 to October Piezometric surface of Cambrian-Ordovician Aquifer in Future water-level decline...43 ILLUSTRATIONS Figure Page 1 Gross sections of the structure and stratigraphy of the bedrock and piezometric profiles of the Cambrian-Ordovician Aquifer in the Chicago region Pumpage from deep wells, 1864 through 1960, subdivided by source Distribution of estimated pumpage from deep wells in Water levels in deep wells in the Chicago, Des Plaines, Elmhurst, and Aurora pumping centers, Water levels in deep wells in the Joliet, Elgin, and Elmhurst pumping centers, Map showing location of selected observation wells i

3 Figure Page 7 Map showing changes in water levels in deep wells 8 Water levels at Malta during Water levels at Zion during 1959 and Elevation of piezometric surface of Cambrian- Ordovician Aquifer in October, TABLES Table Page 1 Distribution of pumpage from deep wells in 1958, 1959, and Distribution of pumpage from deep wells in 1959 and 1960, subdivided by use Decline in nonpumping water levels, , October 1958 to October 1959, and October 1959 to October Water levels in deep wells in northeastern Illinois in Decline in water levels in deep wells during ii

4 WATER-LEVEL DECLINE AND PUMPAGE DURING 1960 IN DEEP' WELLS IN THE CHICAGO REGION, ILLINOIS by R. T. Sasman, T. A. Prickett, and R. R. Russell SUMMARY The water-level decline during 1960 in deep wells penetrating the Cambrian-Ordovician Aquifer, the most highly developed aquifer for large ground-water supplies in the Chicago region, is considered in this report. The Cambrian-Ordovician Aquifer is encountered at an average depth of about 500 feet below the land surface at Chicago; it has an average thickness of 1000 feet and is composed chiefly of sandstones and dolomites. Pumpage from deep wells has increased from 200,000 gallons per day (gpd) in 1864 to 88.0 million gallons per day (mgd) in As a result, artesian pressure in the Cambrian-Ordovician Aquifer at Chicago has declined about 670 feet. Pumpage from deep wells is concentrated in six centers: Chicago area, Joliet area, Elmhurst area, Des Plaines area, Aurora area, and Elgin area. In 1960, pumpage from deep wells was 91.7 mgd or 3.7 mgd more than in This annual increase in pumpage has resulted in excessive declines in water levels in deep wells. Waterlevel declines during 1960 ranged from 11 feet in the Elgin area to 18 feet in the Des Plaines area and averaged about 13 feet The 1960 average decline is much greater than the average annual rate of decline (10 feet) for the period Withdrawals in 1960 exceed the practical sustained yield of the Cambrian-Ordovician Aquifer as they did in 1959, with the 3

5 4 result that ground-water users in the Chicago region continue to mine water and to borrow water from future generations. If the distribution of pumpage remains the same as in 1960 and pumpage from the Cambrian-Ordovician Aquifer continues to increase in the future, the lowest and most permeable unit of the aquifer will be partially dewatered in many areas much sooner than previously anticipated,, Pumping levels exceeding 1000 feet below the surface will be common within 20 years. INTRODUCTION In May 1959 the State Water Survey and the State Geological Survey issued Cooperative Ground-Water Report 1, entitled "Preliminary Report on Ground-Water Resources of the Chicago Region, Illinois." (1) Cooperative Report 1 discussed the geology and hydrology of the ground-water resources of the Chicago region, the yields of aquifers, and the possible consequences of future ground-water development. Special emphasis was placed on the deep water-yielding aquifers which have been most widely used for large ground-water supplies. Studies described in Cooperative Report 1 indicated that pumpage from deep wells during 1958 approached the amount that could be continuously withdrawn without eventually dewatering the lowermost and most productive formation of the deep aquifer. Future ( ) water-level declines, ranging from (1) Suter, Max, Bergstrom, R. E., Smith, H. F., Emrich, G. H., Walton, W. C., and Larson, T. E., 1959, Preliminary Report on Ground-Water Resources of the Chicago Region, Illinois: Cooperative Ground- Water Report 1, Illinois State Water Survey and State Geological Survey.

6 190 feet at Elgin to 300 feet at Chicago and Des Plaines, were predicted,, It was recognized that actual water-level declines will vary from predicted declines given in the report if future distribution and rates of pumpage deviate from extrapolations of past ground-water use,, As a result of the findings of Cooperative Report 1, the program of collecting and reporting water-level and pumpage data for deep wells in the Chicago region, which is one of the functions of the State Water Survey, was accelerated in The objectives of the program are (1) to provide a year to year evaluation of trends in water levels and pumpage, (2) to delineate problem areas, (3) to provide long-term continuous records of fluctuations of water levels and pumpage, and (4) to collect and report all hydrologic information which will facilitate the planning and development of the water resources of the deep aquifer in the Chicago region. The program is particularly urgent at this time due to the progressively increasing demands; for water supplies and the continuing decline of water levels. In May 1960 the State Mater Survey issued Circular 79* entitled "Water Level Decline and Pumpage During 1959 in Deep Wells (2) in the Chicago Region, Illinois," This report summarized the trends in water levels and pumpage from deep wells during Pumpage from deep wells in 1959 was 88.0 mgd or 9.7 mgd more than in This annual increase in pumpage was record high, exceeded the practical sustained yield (46 mgd) of the deep aquifer, and (2) Walton, W. C., Sasman, R. T., and Russell, R. R., 1960, Water Level Decline and Pumpage During 1959 in Deep Wells in the Chicago Region, Illinois: Circular 79, Illinois State Water Survey. 5

7 6 resulted in excessive declines in water levels in deep wells. Waterlevel declines during 1959 ranged from 9 feet in the Joliet area to 41 feet in the Elmhurst area and averaged about 20 feet in the Chicago region. The 1959 average decline was much greater than the average annual rate of decline (10 feet) for the period This report summarizes trends in water levels and pumpage from deep wells during A summary of the essential findings of Cooperative Report 1 and Circular 79 regarding the deep aquifers is presented to serve as a background for interpretation of the records. GEOLOGY AND HYDROLOGY OF CAMBRIAN-ORDOVICIAN AQUIFER Ground water resources in the Chicago region are developed from four aquifer systems: (1) sand and gravel deposits of the glacial drift; (2) shallow dolomite formations, mainly of Silurian age; (3) the Cambrian-Ordovician Aquifer; and (4) the Mt. Simon Aquifer. This report is concerned with the Cambrian-Ordovician Aquifer. The Cambrian-Ordovician Aquifer consists in downward order of the Galena-Platteville Dolomite, Glenwood-St. Peter Sandstone, and Prairie du Chien Series of Ordovician age; Trempealeau Dolomite, Franconia Formation, and Ironton-Galesville Sandstone of Cambrian age. The sequence, structure, and general characteristics of these rocks are shown in figure 1. The Cambrian-Ordovician Aquifer is separated from the Mt. Simon Aquifer by shale beds of the Eau Claire Formation. The Maquoketa Formation above the Galena-Platteville Dolomite acts as a barrier between the shallow dolomite and deeper

8 FIGURE 1. CROSS SECTIONS OF THE STRUCTURE AND STRATIGRAPHY OF THE BEDROCK AND PIEZOMETRIC PROFILES OF THE CAMBRIAN-ORDOVICIAN AQUIFER IN THE CHICAGO REGION

9 8 aquifers and confines the water in the deeper aquifers under artesian pressure. Available data indicate that on a regional basis the entire sequence of strata, from the top of the Galena-Platteville to the top of the shale beds of the Eau Claire Formation, behaves hydraulically as one aquifer. The Ironton-Galesville Sandstone is the most productive formation of the Cambrian-Ordovician Aquifer. The Galena-Platteville Dolomite and Prairie du Chien Series generally are not well creviced and are not major contributors. The Trempealeau Dolomite is locally well creviced. The Cambrian-Ordovician Aquifer receives water from overlying glacial deposits mostly in areas of Kane, McHenry, Kendall, Boone, and DeKalb Counties where the Galena-Platteville Dolomite is the uppermost bedrock formation below the glacial deposits. This is west of the border of the Maquoketa Formation. Recharge of the glacial deposits occurs from precipitation that falls locally. Vertical leakage of water through the Maquoketa Formation into the Cambrian-Ordovician Aquifer is becoming appreciable under the influence of large differentials in head between shallow deposits and the Cambrian-Ordovician Aquifer. PUMPAGE FROM DEEP WELLS The first deep well in Chicago, drilled at the corner of Chicago and Western Avenues in l864, had an artesian flow estimated at about 150 gallons per minute (gpm) or about 200,000 gpd. The estimated pumpage from deep wells in the Chicago region increased gradually from 200,000 gpd in to 88 mgd in 1959 as shown in figure 2.

10 Figure 2. PUMPAGE FROM DEEP WELLS, 1864 THROUGH 1960, SUBDIVIDED BY SOURCE 9

11 10 Many deep wells in the Chicago region are either uncased or faultily cased in the Silurian age dolomite and allow leakage. The Mt. Simon Aquifer also is penetrated by a large number of deep wells, particularly along the Pox River in Kane County. The artesian pressure of the Cambrian-Ordovician Aquifer is lower than that in the Silurian age dolomite and Mt. Simon Aquifer. Ground water, therefore, moves downward from the dolomite and upward from the Mt. Simon into the Cambrian-Ordovician Aquifer through wells that are open in all three aquifers. Thus, water pumped from deep wells does not come from the Cambrian-Ordovician Aquifer alone. It is estimated that of the 88 mgd pumped from deep wells in 1959, 50 mgd came from the Cambrian-Ordovician Aquifer, 24 mgd came from the Silurian age dolomite, and 14. mgd came from the Mt. Simon Aquifer. Pumpage in 1960 During 1960 pumpage from deep wells increased from 88.0 mgd to 91.7 mgd, an increase of 3.7 mgd. This increase is less than 40 per cent of the increase during Total pumpage in 1960 was about 4 per cent greater than total pumpage in It is estimated that of the 91.7 mgd pumped from deep wells during 1960, 52.3 mgd came from the Cambrian-Ordivician Aquifer, and 39.4 mgd came from the Silurian age dolomite and Mt. Simon Aquifer. Pumpage is concentrated in six centers: the Chicago, Joliet, Elmhurst, Des Plaines, Aurora, and Elgin areas. Distribution of pumpage from deep wells in 1958, 1959, and 1960 is shown in table 1. The greatest quantities of water were withdrawn from deep wells in the Chicago, Joliet, and Aurora areas.

12 11 Table 1 - Distribution of Pumpage from Deep Wells in 1958, 1959, and 1960 Pumping Center Total pump age (mgd) Pump age increase (mgd) Chicago area Joliet area Elmhurst area Des Plaines area Elgin area Aurora area negligible 1.3 negligible Total Pumpage increases, , in all pumping centers were much less than pumpage increases, As shown in table 1, pumpage increases, , in the six pumping centers ranged from negligible in the Chicago and Elmhurst areas to 1.3 mgd in the Joliet area. Pumpage increases exceeding 1.0 mgd were recorded for the Joliet, Des Plaines, and Aurora areas. The rate of pumpage increase, , is more than 4 times the average annual rate of pumpage increase, l During 1960, 10 new deep wells were placed in operation. Of these wells, 5 were drilled to augment existing municipal wells or to develop new municipal or subdivision water supply systems. A number of deep wells and deep well pumps were rehabilitated to meet increased demands. The distribution of pumpage in 1959 and 1960, subdivided by use, is shown in figure 3 and in table 2. Public use includes municipal and institutional pumpage. No attempt has been made to determine the final use of water within categories. Any water pumped by a municipality is called a public supply, regardless of the use of the water.

13 12 Figure 3. DISTRIBUTION OF ESTIMATED PUMPAGE FROM DEEP WELLS IN 1960

14 Table 2 - Distribution of Pumpage from Deep Wells in 1959 and 1960, Subdivided by Use 13 Pumping Center Chicago area Joliet area Elmhurst area Des Plaines area Elgin area Aurora area Total Public pumpage (mgd) Industr ial pumpage (mgd) In 1960 withdrawals for public water-supply systems amounted to about 58 per cent of the total pumpage;: industrial pumpage was about 42 per cent of the total. Municipal pumpage was 48.4 mgd or 90 per cent of the total public pumpage. Municipal pumpage continues to be by far the greatest use in the Elmhurst, Des Plaines, Elgin, and Aurora areas,, Most industrial pumpage is concentrated in the Chicago and Joliet areas. Public pumpage in 1960 was about 5 per cent greater than in 1959; industrial pumpage in 1960 was about 3 per cent greater than in Public pumpage increases, , were greatest in the Des Plaines area (1.2 mgd); in the Elmhurst and Elgin areas there was a decrease of 0.1 mgd in the public pumpage. Increases in public pumpage of 0.6 mgd, 0.2 mgd, and 0.7 mgd were reported in the Chicago, Joliet, and Aurora areas, respectively. Much of the increase in public pumpage was recorded for deep wells owned by large municipalities, such as Arlington Heights, Bellwood, Des Plaines, Elgin, Joliet, Lombard, Mt. Prospect, and St. Charles. A number of subdivisions also showed a considerable increase in pumpage. Municipal pumpage from deep wells decreased at some

15 14 municipalities, such as Aurora, Elmhurst, Geneva, and Villa Park. Of the twelve municipalities which pumped more than 1.0 mgd during 1960, eight recorded an average increase of 0.2 mgd and four recorded an average decrease of 0.1 mgd. Industrial pumpage increased 1.1 mgd in the Joliet area where several industries increased their use of ground water. Industrial pumpage in the Chicago area decreased 0.6 mgd. The other four areas reported negligible change or small increases (0.1 to 0.3 mgd) in industrial pumpage. In the Chicago region, seven industries reported pumpage of more than 1.0 mgd in 1960, two reported an average increase of 0.6 mgd, three reported an average decrease of 0.1 mgd, and two reported negligible change in pumpage during Data on industrial pumpage were obtained at 114 plants. As in previous years, a few industries abandoned their deep wells and converted to municipal systems, and a few industries developed new deep well supplies. Total industrial pumpage increased 1.2 mgd. In the six pumping centers, only one municipality developed a new deep well water supply during 1960s two subdivisions developed new deep well supplies. One municipality rehabilitated an existing shallow ground-water supply and placed its deep well on a stand-by basis. Practical Sustained Yield of Cambrian-Ordovician Aquifer in Relation to Pumpage in 1960 In Cooperative Report 1 it was estimated that the practical sustained yield of the Cambrian-Ordovician Aquifer is about 46 mgd and would be developed when the total pumpage from deep wells is

16 15 about 81 mgd. The practical sustained yield of the aquifer is the maximum amount of water that can be withdrawn without eventually dewatering the most productive water-yielding formation, the Ironton-Galesville Sandstone. The practical sustained yield is largely limited by the rate at which water can move from recharge areas eastward through the aquifer to pumping centers. Based on past records of pumpage and water levels, it was estimated in Cooperative Report 1 that the practical sustained yield would be exceeded by However, total pumpage from deep wells in 1959 and in 1960 actually exceeded the withdrawal rate anticipated for Thus, the practical sustained yield of the aquifer was exceeded in 1959, and during 1960 ground-water users in the Chicago region continued to mine water and to borrow water from future generations. Sustained pumping at the 1960 rate will result in the dewatering of the Ironton-Galesville Sandstone in many parts of the Chicago region much sooner than anticipated in Cooperative Report 1 with a great and continual reduction in yields of wells. WATER LEVELS IN DEEP WELLS In 1864 the artesian pressure in the Cambrian-Ordovician Aquifer was sufficient to cause wells to flow in many parts of the Chicago region. The average elevation of water levels in deep wells at Chicago and at Joliet was probably about 700 feet. As a result of continued heavy pumping, the nonpumping water levels in deep wells declined in 1959 to elevations of 50 feet at Summit southwest of Chicago and 25 feet at Joliet. Prom the artesian pressure at Chicago declined about 670 feet. The average rate of decline l was about 7 feet

17 16 per year. The greatest water-level declines in the Chicago region, amounting to more than 650 feet, have occurred in areas of heavy pumpage at Summit and at Joliet. The total decline has been 10 feet or less in recharge areas in Boone and DeKalb Counties. Examples of long-term fluctuations in water levels in the Chicago region are shown in figures 4 and 5. Hydrographs of observation wells in the Cambrian-Ordovician Aquifer show a steady decline of water levels largely as a result of the continued increase of withdrawals by municipalities, industries, institutions, and commercial establishments as shown in figure 2. The locations of the observation wells for which hydrographs are given in this report are shown in figure 6. The average annual rates of decline for the period 1945 through 1959 in pumping centers are given in table 3. Table 3 - Decline in Nonpumping Water Levels, , October 1958 to October 1959, and October 1959 to October 1960 Pumping Center Chicago area Joliet area Elmhurst area Des Plaines area Elgin area Aurora area Average decline (feet per year) Average dec (fe et) line 0ct Oct Oct Oc t Prom 1945 through 1959, the average annual decline in water levels ranged from 14 feet in wells in the Elmhurst area to 7 feet in wells near the center of Jolieto The average annual decline exceeded 10 feet in the Elmhurst, Des Plaines, and Elgin areas.

18 17 Figure 4. WATER LEVELS IN DEEP WELLS IN THE CHICAGO, DES PLAINES, ELMHURST, AND AURORA PUMPING CENTERS,

19 18 Figure 5. WATER LEVELS IN DEEP WELLS IN THE JOLIET, ELGIN, AND ELMHURST PUMPING CENTERS,

20 Figure 6. MAP SHOWING LOCATION OF SELECTED OBSERVATION WELLS

21 20 Water-Level Decline, October 1959 to October 1960 The water levels in 240 deep wells in the Chicago region were measured during the last week in October and the first week in November, Data for the wells are given in table 4. Water levels in 143 of these wells were also measured during the same period in Water-level data for 1959 were compared with data for 1960; computed declines and rises are given in table 5. Computed declines and rises and the piezometric surface maps for 1959 and 1960 were used to construct figure 7<> Data were not sufficient to accurately describe water-level changes in the southern parts of Will and LaSalle Counties and in Grundy, Kankakee, and Livingston Counties. The average declines in nonpumping water levels, October 1959 to October 1960, for each pumping center based on figure 7 are given in table 3. As shown by figure 7 the water-level decline varies from place to place within pumping centers. For example, water levels in deep wells in some places in the Chicago area pumping center recovered; however, on an average water levels declined about 13 feet. The greatest average decline occurred in the Des Plaines area pumping center; the least average decline was recorded for the Elgin area pumping center. Average declines exceeding 10 feet were computed in all pumping centers. The increase in pumpage in 1960 (3.7 mgd) was much less than the increase in pumpage during 1959 (9.7 mgd), and as a result, the time-rate of water-level decline decreased greatly during Average declines during 1960 were several feet less than average declines during 1959 in the Elmhurst, Des Plaines, Elgin, and

22 Table 4 - Water Levels in Deep Wells in Northeastern Illinois in 1960 Elevations in Feet Above Mean Sea Level Well No. Owner Depth of well (feet) *BNE 44N3E-24.8a City of Belvidere 87O BNE BNE 44N3E-25.8b 44N3E-26.1el City of Belvidere City of Belvidere BNE 44N3E-35.le2 City of Belvidere 610 COK 42N12E-2.5b Green Acre Countrv Club 1362 COK COK 42N12E-14.2cl 42N12E-23.5f3 Sunset Ridge Country Club Holy Ghost Convent COK 42Nl2E-28.7e Signode Steel Strapping Co COK 42N12E-29.la Illinois Municipal Water Co COK 42N12E-33.2c Illinois Municipal Water Co. 917 Surface elevation Depth to water (feet) Water level elevation -;:-The well numbering system used in this report is based on the location of the well, and uses the township, range, and section for identification Date /2 11/2 11/2 11/2 10/24 10/24 11/4 11/3 11/3 11/3 The well number consists of five parts: county abbreviation, township, range, section, and coordinate within the section. Sections are divided into rows of one-eighth mile squares. Each one-eighth mile square contains 10 acres and corresponds to a quarter of a quarter of a quarter section. A normal section of one square mile contains eight rows of eighth-mile squares; an odd-size section contains more or fewer rows. Rows are numbered from east to west and lettered from south to north as shown below. Cook County T.41N., R. 11E. sec. 25 The number of the well shown in sec. 25 above is as follows: COK 41N11E-25.4g. Where there is more than one well in a 10-acre square they are identified by arablc numbers after the lower case letter in the well number.

23 Table 4 - (continued) Well No. Owner Depth of well (feet) Surface elevation Depth to water (feet) Water level elevation Date 1960 COK 42N11E-ll.6e COK 42N11E-11.8b2 COK 42N11E-16.7a GOK 42N11E-26.7d COK 42N11E-27.3a Village of Wheeling Ekco Foil Container Corp. Arlington Vista Utility Co. Brickman Manor Subdivision Village of Mt. Prospect /24 10/25 11/3 ll/l6 6/28 COK 42N11E-33.3b COK 42N11E-34.4g COK 42N11E-36.3b2 COK 42N11E-30.3b COK 42N10E-24.8al Village of Mt. Prospect Village of Mt. Prospect Maryville Academy Village of Arlington Heights Arlington Heights Jockey Club l /1 11/1 9/20 11/15 10/28 COK 42N10E-25.lb COK 41N13E-8.6d COK 41N13E-l8.5g COK 41N13E-20.7e COK 41N13E-21.2b COK 41N12E-12.8b COK 41N12E-l8.lh COK 41N12E-19.5g COK 41N11E-10.3f COK 41N11E-12.8h2 City of Rolling Meadow Glenview Club Avon Products, Inc. Baxter Laboratory G. D. Searle & Co. Eugenia Subdivision Benjamin Electric Co. City of Des Plaines Island Lake Water Co. Village of Mt. Prospect /14 11/3 11/3 10/31 11/4 11/3 10/24 3/15 11/3 11/1 COK 41N11E-13.4a COK 41N11E-21.3b COK 41N11E-24.lg2 COK 40N12E-l8.6c COK 40N12E-31.4c City of Des Plaines Village of Elk Grove Citizens Utilities Co. of Ill. J. B. Clow & Sons, Inc. Automatic Electric Co /4 11/16 10/21 COK 40N12E-31.4d COK 39N13E-13.3c COK 39N13E-21.6g COK 39N13E-25.2g COK 39N13E-35.1h Automatic Electric Co. Superior Sleeprite Corp. Kropp Forge Co. Ideal Roller & Mfg. Co. Liquid Carbonic Corp /21 11/2 3/31 2/22 10/31

24 Table 4 - (continued) Well No. Owner Depth of well (feet) Surface elevation Depth to water (feet) Water level elevation Date 1960 GOK 39N12E-4.2b2 COK 39N12E-9.3g COK 39N12E-.ll.7f COK 39N12E-12.3e GOK 39N12E-13.7g Richardson Co. City of Bellwood Village of Maywood Bowman Dairy Co. Altenheim-German Home /12 11/1 10/26 10/26 11/1 COK 39N12E-25.5d COK 39N12E-36.8d COK 38N14E-5.2h COK 38N14E-7.6c COK 38N14E-7.7g2 COK 38N13E-11.1h COK 38N13E-19.4el COK 38N13E-21.1f COK 38N12E-5.8d2 COK 38N12E-l8.8f3 Village of Riverside Village of Riverside Produce Terminal Corp. Fleischmann Malting Co. Standard Brands, Inc. Bradshaw-Praeger & Co. Visking Corp. Cracker Jack Co. Village of Western Springs Suburban Cook Co. T.B. Sanitarium /23 10/23 5/26 10/25 8/30 11/9 10/24 10/10 7/5 11/1 COK 38N12E-24.7h COK 38N12E-28.7d COK 38N12E-29.1d COK 37Nl5E-8.1b2 COK 37N13E-32.5h2 Corn Products Co. Fisher Body Co. Fisher Body Co. Columbia Malting Co. Ridgeland Water Service Co /30 11/14 11/14 10/20 10/12 COK 37N11E-20.4d COK 36N14E-2.8e COK 36N14E-3.1g COK 36N14E-34.5g COK 36N13E-1.2c Village of Lemont Kaiser-Aluminum & Chemical Corp. Metro Glass Co. Village of Thornton Miller Pre-Pared Potato Co /24 8/15 8/6 10/25 10/25

25 Table 4 - (continued) Well No. Owner Depth of well (feet) Surface elevation Depth to water (feet) Water level elevation Date 1960 GOK 36N13E-9.8b2 COK 35N14E-21.3h El Vista Calumet Subdivision Steel Co J4.O /25 10/15 DEK 42N5E-19.4.b DEK 42N5E-19.6b2 DEK 42N4E-22.7a3 DSK 42N3E-26.3hl DEK 42N3E-26.3h2 DEK 4lN5E-32.3e2 DEK 4lN5E-32.6c DEK 40N4E-15.7a DEK 40N4E-22.3el DEK 40N4E-23.2e DEK 40N4E-23.4d DEK 40N3E-23.6e DEK 40N3E-23.7e DEK 40N3E-23.8el DEK 38N5E-l5.2d City of City of Village Village Village City of City of City of City of City of City of Village Village Chicago road Village Genoa Genoa of Kingston of Kirkland of Kirkland Sycamore Sycamore DeKalb DeKalb DeKalb DeKalb of Malta of Malta & Northwestern Railof Hinckley i ) /4 10/25 10/26 DEK 37N5E-32.1cl DEK 37N5E-32.1c2 DEK 37N5E-36.7gl DEK 37N5E-36.7hl DUP 40N11E-13.4b DUP 40N11E-13.8el DUP 40N11E-14.4e DUP 40N11E-31.5b DUP 40N11E-35.5e Village of Somonauk Village of Somonauk Oatman Dairy Village of Sandwich Chicago, Milwaukee, St. Paul & Pacific Railroad Village of Bensenville Village of Bensenville Village of Lombard City of Elmhurst /26 10/26 10/26 10/26 11/3 10/4 10/4 11/19 11/22

26 Table 4 - (continued) Well No. Owner Depth of well (feet) Surface elevation Depth to water (feet) Water level elevation Date 1960 DUP 40N10E-14.8dl DUP 39N11E-2.2f DUP 39N11E-9.1h DUP 39N11E-9.2h DUP 39N11E-10.1h Suncrest Highlands Sewage & Water Co. City of Elmhurst Village of Villa Park Village of Villa Park City of Elmhurst /2 7/29 10/24 6/6 10/24 DUP 39N11E-10.4g6 DUP 39N11E-12.8d DUP 39N10E-l.4d DUP 39N9E-l5.7h DUP 38N9E-13.2b3 Ovaltine Food Products City of Elmhui'st Public Service Co. of N.I11. City of West Chicago City of Naperville /30 6/24 10/24 10/24 9/12 DUP 37N11E-3.8al GRY 34N8E-35.1e GRY 33N8E-36.5a GRY 33N7E-4.4a GRY 33N7E-9.3h KNE 42N8E-22.4g KNE 42N8E-22.7f KNE 42N8E-27.1e KNE 4.2N6E-3.le KNE 41N8E-11.3fl KNE 41N8E-11.3f2 KNE 41N8E-11.3f4. KNE 41N8E-11.3f5 KNE 41N8E-12.3e KNE 41N8E-24.3b3 Argonne National Laboratory Dresden Nuclear Power Sta. Village of Diamond Brown Milling Co. City of Morris Village of Carpentersville D. Hill Nursery Co. Village of West Dundee Illinois Toll Highwav Comm. M-6 City of Elgin City of Elgin City of Elgin City of Elgin Simpson Co. City of Elgin /15 8/1 11/4 10/25 10/25 11/2 11/2 11/2 11/8 10/9 10/30 10/30 10/30 11/4 5/30

27 Table 4 - (continued) Well No. Owner Depth of well (feet) Surface elevation Depth to water (feet) Water level elevation Date 1960 KNE 41N8E-24.6hl KNE 41N8E-24.6h2 KNE 41N6E-9.lg2 KNE 40N8E-27.6b KNE 40N8E-31.6h Elgin National Watch Co. Elgin National Watch Co. Village of Burlington City of St. Charles Ill. State Training School for Boys /1 11/1 10/11 11/3 11/15 KNE 40N8E-34.5g2 KNE 40N8E-34.6el KNE 40N6E-30.4d KNE 39N8E-2.4c KNE 39N8E-3.1b2 KNE 39N8E-3.5e KNE 39N8E-3.8g KNE 39N8E-22.3el KNE 39N8E-22.3e2 KNE 39N8E-23.8f ME 39N8E-33.4g KNE 39N8E-35.5g KNE 39N7E-5.8f KNE 39N7E-6.3fl KNE 39N7E-10.4g KNE 38N8E-4.3g KNE 38N8E-4.4b KNE 38N8E-9.2d KNE 38N8E-13.8b KNE 38N8E-l5.4gl KNE 38N8E-l5.5e KNE 38N8E-l5.6h KNE 38N8E-l6.4d KNE 38N8E-21.5h Howell Co. City of St. Charles C. Clyne City of Geneva City of Geneva Burgess Norton Co. City of Geneva City of Batavia City of Batavia City of Batavia Mooseheart Mooseheart Village of Elburn Elburn Packing Co. Broadview Academy Village of North Aurora Aurora Downs Racetrack Mercyville Aurora Paperboard Co. City of Aurora Aurora Bleaching, Inc. Alba Mfg. Co. City of Aurora City of Aurora /3 11/3 10/15 10/20 10/19 11/3 10/30 10/28 10/28 10/28 11/3 11/3 11/3 7/18 10/28

28 Table 4 - (continued) Well No. Owner Depth of well (feet) Surface elevation Depth to water (feet) Water level elevation Date 1960 KNE 38N8E-22.7c KNE 38N8E-27.5a KNE 38N8E-29.2h KNE 38N8E-32.4f KNE 38N8E-33.8c City of Aurora City of Aurora City of Aurora Village of Montgomery Village of Montgomery KNK 30N9E-6.8a Village of Reddick /28 KEN 37N8E-6.2d KEN 37N8E-6.2f KEN 37N8E-17.6b KEN 37N8E-20.8h KEN 37N7E-32.1el KEN 37N7E-32.1e2 Caterpillar Tractor Co. Caterpillar Tractor Co. Village of Oswego Village of Oswego Village of Yorkville Village of Yorkville /3 11/1 10/25 10/26 10/24 11/23 LKE 46N12E-21.3d LKE 46N11E-27.3a LKE 45N11E-14.5a LKE 45N11E-l5.8f LKE 45N10E-26.7b Shiloh Park Central Pur-Food Co. Village of Gurnee Ill.Toll Highway Comm. M-4 Village of Grays Lake /26 10/26 10/25 10/25 10/25 LKE 45N10E-26.8b LKE 44N12E-l8.3f2 LKE 44N12E-21.6g LKE 44N12E-21.8f2 LKE 44N11E-l8.4a LKE 43N12E-31.5f Village of Grays Lake Goodyear Tire & Rubber Co. Methodist Children's Home Village of Lake Bluff St. Mary's of the Lake Seminary Ill. Toll Highway Comm. TP /25 10/25 10/25 10/25 10/24 10/24 LAS 36N4E-8.5hl LAS 36N4E-8.5h2 LAS 36N3E-18.4d2 LAS 36N3E-18.4d3 LAS 36N3E-18.10a Village of Leland Village of Leland City of Earlville City of Earlville Marathon Electric Co /26 10/26 10/26 10/26 10/24

29 Table 4 - (continued) Well No. Owner Depth of well (feet) Surface elevation Depth to water (feet) Water level elevation Date 1960 LAS 36N1E-32.1a LAS 35N5E-8.6b LAS 33N5E-25.4gl LAS 33N2E-21.2g LAS 33N2E-21.3g City of Mendota Ill. State Industrial School U.S.Government (Civil Defense Agency) Starved Rock State Park Starved Rock State Park /26 11/23 10/25 11/2 11/2 LEE 37N2E-10.2b LEE 37NlE-8.8e3 Village of Paw Paw Village of West Brooklyn /26 10/26 LIV 30N8E-26.8h I.IV 30N6E-1.2a Cardiff Ill. State Reformatory for Women /28 10/28 MCH 46N5E-33.8a MCH 45N8E-10.8d MCH 44N9E-20.1b MCH 44N8E-33.5a MCH 44N5E-35.3g Dean Milk Co Morton Chemical Co. Island Lake Water Co. City of Crystal Lake City of Marengo /28 MCH 44N5E-35.5h MCH 43N8E-5.4g Arnold Engineering Co. City of Crystal Lake /8 10/28 OGL 40N2E-23.1f OGL 40N1E-24.5h OGL 40NlE-24.7al OGL 40NlE-24.7a2 OGL 40N1E-25.3f OGL 40N1E-25.8h Village of Creston City of Rochelle City of Rochelle City of Rochelle City of Rochelle City of Rochelle WIL 37N10E-25.7c WIL 37N10E-26.1a WIL 36N10E-2.8f WIL 36N10E-l6.4d WIL 36N10E-23.2f Pure Oil Co. Pure Oil Co. Public Service Co.of N. Ill. Sta. 18 Revere Copper & Brass Co. City of Lockport /25 10/25 10/25 11/9 10/1

30 Table 4 - (continued) Well No. Owner Depth of well (feet) Surface elevation Depth to water (feet) Water level elevation Date 1960 WIL 36N10E-23.5a WIL 36N10E-23.6c WIL 36N-10E-27.6b WIL 36N10E-28.6f2 WIL 36N10E-28.6g City of Lockport 1571 City of Lockport 1446 U. S. Army Lockport Locks 815 Ill. State Penitentiary, 2007 Stateville Ill. State Penitentiary, 1600 Stateville /9 10/3 11/9 ll/l 9/2 WIL 36N10E-28.6h WIL 36N10E-29.2g WIL 36N10S-32.1a WIL 36N10E-33.6h WIL 36N10E-33.8e Ill. State Penitentiary, Stateville Ill. State Penitentiary, Stateville Lidice Subdivision Public Service Co. Sta. 55 of N. Ill.,. Lidice Subdivision /2 10/24 9/22 10/17 10/12 WIL 36N10E-34.8a WIL 36N9E-10.8d WIL 35N11E-8.8h WIL 35N10E-3.4e WIL 35N10E-3.5e WIL 35N10E-4.2h WIL 35N10E-9.1d WIL 39N10E-10.1a WIL 35N10E-10.6a WIL 35N10E-11.6g WIL 35N10E-16.2h WIL 35N10E-20.6a WIL 35N10E-20.7g WIL 35N10E-21.4b WIL 35N10E-22.3f Ruberoid Co. Village of Plainfield City of Joliet (Hadley Valley) Ill. State Penitentiary Ill. State Penitentiary Phoenix Mfg. Co. City of Joliet Wm.E. Pratt Mfg. Co. Joliet Twp. High School. E. J. & E. R. R. City of Joliet Public Service Co. of N.I11. Sta. 9 Village of Rockdale American Cyanamid Co. Will County Sanitarium /2 10/25 10/17 11/2 11/1 10/18 11/7 11/7 10/18 10/24 10/17 10/9 11/14 10/14 10/18

31 Table 4 - (continued) Well No. Owner Depth of well (feet) Surface elevation Depth to water (feet) Water level elevation Date 1960 WIL 35N10.E-22.7g WIL 35N10E-30.3C WIL 35N10E-30.6e WIL 35N10E-30.7f WIL 34N9E-10.1h WIL 34N9E-11.2e WIL 34N9E-11.7g WIL 33N9E-1.5el American Institute of Laundering Blockson Chemical Co. Caterpillar Tractor Co. Caterpillar Tractor Co. American Oil Co. Stepan Chemical Co. American Oil Co. Joliet Arsenal, Kankakee /18 9/21 9/2 9/2 10/4 11/10 10/24 10/17 WIN 44N2E-l8.6b WIN 44N2E-20.3e WIN 44N2E-31.7f WIN 44N1E-2.3b WIN 44N1E-21.8e City of Rockford City of Rockford City of Rockford City of Rockford City of Rockford /28 11/9 7/28 7/28 WIN 44N1E-23.7e WIN 44N1E-34.6h WIN 44N1E-36.7fl City of Rockford City of Rockford City of Rockford /28

32 31 Table 5 - Decline in Water Levels in Deep Wells During 1960 Well No. BNE 44N3E-24.8a BNE 44N3E-35.1e2 COK 42N12E-2.5b COK 42N12E-14.2cl COK 42N12E-28.7e COK 42N12E-29.la COK 42N11E-11.6e COK 42N11E-11.8b2 COK 42N11E-l6.7a COK 42N11E-26.7d COK 42N11E-34.4g COK 42N10E-24.8al COK 41N13E-8.6d COK 41N13E-20.7e COK 41N13E-21.2b COK 41N12E-12.8b COK 41N11E-10.3f COK 41N11E-21.3b COK 40N12E-l8.6c COK 40N12E-31.4c COK 40N12E-31.4d COK 39N13E-13.3c COK 39N13E-21.6g COK 39N13E-25.2g COK 39N13E-35.1h COK 39N12E-11.7f COK 39N12E-12.3e COK 39N12E-25.5d COK 39N12E-36.8d COK 38N14E-7.6c COK 38N13E-11.1h COK 38N13E-19.4el Owner City of Belvidere City of Belvidere Green Acre Country Club Sunset Ridge Country Club Signode Steel Strapping Co. Illinois Municipal Water Co. Village of Wheeling Ekco Foil Container Corp Arlington Vista Subdivision Citizens Utilities Co. of Ill. Village of Mt. Prospect Arlington Heights Jockey Club Glenview Club Baxter Laboratory G. D. Searle & Co. Eugenia Subdivision Hatlen Heights Subdivision Village of Elk Grove J. B. Clow & Sons Inc. Automatic Electric Co. Automatic Electric Co. Superior Sleeprite Corp. Kropp Forge Co. Ideal Roller & Mfg. Co. Liquid Carbonic Corp. Village of Maywood Bowman Dairy Co. Village of Riverside Village of Riverside Fleischmann Malting Co. Bradshaw-Praeger & Co. Visking Corp. Water Level Elevation Date of Measurements 10/59-11/60 10/59-11/60 11/59-11/60 11/59-11/60 10/59-11/60 10/59-11/60 10/59-11/60 11/59-11/60 11/59-11/60 11/59-11/60 10/59-11/60 11/59-11/60 11/59-3/60 11/59-2/60 11/59-11/60 Chan ge in Water Level Elevation (f eet) +10*

33 32 Table 5 - (continued) Well No. Owner Water Level Elevation Date of Measurements Chan ge in Water Level Elevation (f eet) COK 38N13E-21.1f COK 38N12E-5.8d2 COK 38N12E-l8.8f3 COK 38N12E-24.7h COK 38N12E-28.7d Cracker Jack Co. Village of Western Springs Suburban Cook Co, T.B. Sanitarium Corn Products Co. Fisher Body Co l /59-7/60 10/59-11/60 10/59-9/60 11/59-11/ COK 37Nl5E-8.1b2 COK 37N11E-20.4d COK 36N14E-3.1g COK 36N13E-1.2c COK 35N14E-21.3h Columbia Malting Co. Village of Lemont Metro Glass Co. Miller Pre-Pared Potato Co. Calumet Steel Co /59-8/ DEK 42N5E-19.4b DEK 42N5E-19.6b2 DEK 42N4E-22.7a3 DEK 42N3E-26.3hl DEK 42N3E-26.3h2 DEK 41N5E-32.6c DEK 40N4E-l5.7a DEK 40N4E-22.3el DEK 40N4E-23.4d DEK 40N3E-23.6e City of Genoa City of Genoa Village of Kingston Village of Kirkland Village of Kirkland City of Sycamore City of DeKalb City of DeKalb City of DeKalb Village of Malta IO/59-IO/6O IO/59-IO/6O IO/59-IO/ DEK 40N3E-23.7e DEK 40N3E-23.8el DEK 38N5E-l5.2d DEK 37N5E-32.1cl DEK 37N5E-32.1c2 DEK 37N5E-36.7hl DEK 37N5E-36.7h2 Village of Malta Chicago & Northwestern Railroad Village of Hinckley Village of Somonauk Village of Somonauk Village of Sandwich Village of Sandwich DUP 40N11E-13.8el DUP 40N11E-14.4e DUP 40N11E-31.5b DUP 40N11E-35.5e DUP 39N11E-9.2h Village of Bensenville Village of Bensenville Village of Lombard City of Elmhurst Village of Villa Park /59-11/60 10/59-11/60 11/59-6/ DUP 39N11E-10.1h DUP 39N10E-l.4d DUP 38N9E-13.2b3 City of Elmhurst Public Service Co. of N. Ill. City of Naperville /59-9/

34 Table 5 - (continued) 33 Well No. Owner Water Level Elevation Date of Chan ge in Measure- Water r Level ments Elevation (feet) GRY 34N8E-35.le GRY 33N8E-36.5a GRY 33N7E-4.4a GRY 33N7E-9.3h Dresden Nuclear Power Sta. Village of Diamond Brown Milling Co. City of Morris /59-8/60 12/59-11/ KNE 42N8E-22.4g KNE 42N8E-27.1e KNE 42N6E-3.1e KNE 41N8E-11.3f2 KNE 41N8E-11.3f4 Village of Carpentersville Village of West Dundee Ill. Toll Highway Coram. M-6 City of Elgin City of Elgin /59-11/60 10/59-11/60 10/59-11/ KNE 40N8E-27.6b KNE 40N8E-31.6h ME L+0N8E-3i+.6el KNE 39N8E-3.1b2 KNE 39N8E-22.3el KNE 39N8E-22.3e2 KNE 39N8E-23.8f KNE 39N8E-33.4g KNE 39N8E-33.5g KNE 39N7E-5.8f KNE 38N8E-9.2d City of St. Charles Ill. State Training School for Boys City of St. Charles City of Geneva City of Batavia City of Batavia City of Batavia Mooseheart Mooseheart Village of Elburn Mercyville Institute /59-11/60 10/59-11/60 10/59-11/60 10/59-11/ KNK 30N9E-6.8a Village of Reddick KEN 37N8E-6.2d KEN 37N8E-6.2f KEN 37N8E-17.6b KEN 37N7S-32.1el Caterpillar Tractor Co. Caterpillar Tractor Co. Village of Oswego Village of Yorkville /59-11/60 10/59-11/60 10/59-11/60 10/59-11/ LKE 46N12E-21.3d LKE 46N11E-27.3a LKE 45N11E-l5.8f LKE 45N10E-26.7b LKE 44N12E-21.8f2 LKE 44N11E-l8.4a LKE 43N12E-31.5f Shiloh Park Central Fur-Food Corp. Ill.Toll Highway Comm. M-L+ Village of Grays Lake Village of Lake Bluff St. Marys of the Lake Seminary Ill.Toll Highway Comm. TP

35 34 Table 5 - (continued) Well No. Owner Water Level Elevation Date of Measurements Change in Wat er Level Ele vation ( feet) LAS 36N4E-8.5hl LAS 36N4E-8.5h2 LAS 36N3E-18.4d3 LAS 36N1E-32.1a LAS 35N5E-8.6b Village of Leland Village of Leland City of Earlville City of Mendota Ill. State Industrial School /59-10/60 10/59-11/ LEE 37N2E-10.2b Village of Paw Paw LIV 30N8E-26.8h Cardiff MCH 46N5E-33.8a MCH 45N8E-10.8d MCH 44N9E-20.1b MCH 44N8E-33.5a MCH 44N5E-35.3g MCH 43N8E-5.4g Dean Milk Co. Morton Chemical Co. Island Lake Water Co. City of Crystal Lake City of Marengo City of Crystal Lake OGL 40N2E-23.1f OGL 40N1E-24.7al Village of Creston City of Rochelle WIL 36N10E-l6.4d WIL 36N10E-23.2f WIL 36N10E-23.5a WIL 36N10E-23.6c WIL 36N10E-27.6b Revere Copper & Brass Co. City of Lockport City of Lockport City of Lockport U.S. Army - Lockport Locks /59-11/60 11/59-11/ WIL 36N10E-28.6f2 WIL 36N10E-28.6h WIL 36N10E-29.2g WIL 36N10E-32.1a WIL 36N10E-33.6h Ill. State Penitentiary, Stateville Ill. State Penitentiary, Stateville Ill. State Penitentiary, Stateville Lidice Subdivision Public Service Co. of N. Ill. Sta /59-11/60 10/59-9/60 11/59-9/ WIL 36N10E-34.8a WIL 35N11E-8.8h WIL 35N10E-3.4e WIL 35N10E-3.5e WIL 35N10E-4.2h Ruberoid Co. City of Joliet (Hadley Valley) Ill. State Penitentiary Ill. State Penitentiary Phoenix Mfg. Co /59-11/60 11/59-11/60 11/59-11/

36 Table 5 - (continued) 35 Well No. Owner Water Level Elevation Date of Measurements Chang e in Wa ter Level Elevation (fe et) WIL 35N10E-9.1d WIL 35N10E-10.1a WIL 35N10E-10.6a WIL 35N10E-16.2h WIL 35N10E-20.6a City of Joliet Wm. E. Pratt Mfg. Co. Joliet Twp. High School City of Joliet Public Service Co. of No. Ill. Sta /59-11/60 11/59-11/ WIL 35N10E-20.7g WIL 35N10E-21.4b WIL 35N10E-22.7g WIL 35N10E-30.6e WIL 35N10E-30.7f Village of Rockdale American Cyanamid Co. American Institute of Laundering Caterpillar Tractor Co. Caterpillar Tractor Co. 119 l /59-11/60 9/59-9/60 9/59-9/ WIL 34N9E-10.1h WIL 34N9E-11.2e WIL 33N9E-1.5el American Oil Co. Stepan Chemical Co. Joliet Arsenal, Kankakee /59-10/60 11/59-11/ WIN 44N1E-23.7e City of Rockford ::- + indicates rise in water level.

37 Figure 7. MAP SHOWING CHANGES IN WATER LEVELS IN DEEP WELLS DURING I960

38 37 Aurora areas. The declines in water levels, October 1959 to October 1960, in the Chicago, Joliet, Des Plaines, and Aurora areas are several feet greater than the average annual rate of water-level decline for the period The average decline, October 1959-October 1960, in the Elmhurst area pumping center is less than the average decline, , because the increase in pumpage during 1960 at Elrahurst was negligible., Superimposed upon the long-term trend of water-level fluctuations in deep wells are seasonal fluctuations caused chiefly by changes in the rate of pumping from nearby wells. Water levels in deep wells in many parts of the Chicago region generally recede during the summer and early fall months, when pumpage is the greatest. Water levels start to recover during the late fall, when pumpage is reduced. Minimum annual water levels are usually recorded during September and October; maximum annual water levels occur during late winter and spring months. Short-term fluctuations reflect intermittent pumping, day-to-day variations in nearby pumping, or changes in atmospheric pressure. As shown by the hydrograph for a well near the village of Malta given in figure 8, the daily and seasonal range in water-level fluctuations in deep wells remote from pumping centers is small. Malta is in the recharge area of the Cambrian- Ordovician Aquifer and is about 65 miles west of Chicago. In the recharge area seasonal variations in water levels closely resemble the annual cycle of water-level changes in shallow wells. The rise of water levels is especially pronounced in the wet spring

39 Figure 8. WATER LEVELS AT MALTA DURING I960

40 months. The 2-foot rise in the water level at Malta, January through December 1960, is in sharp contrast to the l8-foot decline in the water level at Maywood during the same period. A well at the city of Zion near the Illinois-Wisconsin state line was equipped with a recording gage in July The hydrograph for the well is given in figure 9. The decline in the well, October 1959-October 1960, about 5 feet, is much less than the average decline, about 13 feet, in the Chicago region during Piezometric Surface of Cambrian-Ordovician Aquifer in 1960 The piezometric surface is an imaginary surface to which water will rise in artesian wells. Figure 10 shows the piezometric surface of the Gambrian-Ordovician aquifer in October Data on nonpumping water levels in table 4 were used to prepare the map. The general features of the piezometric surface map for 1960 differ but little from those of the piezometric surface map for 1959 as shown in Circular 79. During 1960 the area of lowest water levels in the Chicago area continued to advance in a northwesterly direction from Summit towards the Elmhurst and Des Plaines areas. The 150-foot piezometric surface contour migrated in a northwesterly direction about two miles from its estimated position in In 1960, the deepest cone of depression in Cook County (about 34 feet above sea level) was in the vicinity of Summit. A pronounced cone of depression is centered in the southwest part of Joliet where large quantities of water are pumped for

41 Figure 9. WATER LEVELS AT ZION DURING 1959 AND I960

42 41 Figure 10. ELEVATION OF PIEZOMETRIC SURFACE OF CAMBRIAN- ORDOVICIAN AQUIFER IN OCTOBER, I960

43 42 industrial use. The average elevation of water levels in deep wells within the corporate limits of Joliet was about 100 feet above sea level in The general rise of water levels in the Libertyville area changed the piezometric surface in parts of Lake County. The 500- foot, 550-foot, and 600-foot contours migrated several miles in a southeasterly direction as the result of decreases in pumpage. Depressions in the piezometric surface are apparent at Summit, Joliet, Elgin, Geneva, Batavia, Elmhurst, Des Plaines, DeKalb, and Aurora, The piezometric surface was below the top of the Galena-Platteville Dolomite in the deepest parts of the cones of depression at Chicago, Elmhurst, Des Plaines, and Joliet. The general pattern of flow of water in the Cambrian- Ordovician Aquifer in 1960 was slow movement from all directions toward the deep cones of depression centered west of Chicago at Summit and Joliet. Some of the water flowing toward Chicago and Joliet is intercepted by cones of depression in the Aurora, Elgin, Des Plaines, and Elmhurst areas. The lowering of the water levels accompanying the withdrawals of ground water has established steep hydraulic gradients west and north of Chicago, and large quantities of water are at present being transmitted from recharge areas in northern Illinois and minor quantities from southern Wisconsin toward centers of pumping. Large amounts of water derived from storage within the Cambrian-Ordovician Aquifer and from vertical leakage of water through the Maquoketa Formation move toward Chicago and Joliet from the east in Indiana, from the south in Illinois, from the west in Illinois, and from the northeast beneath Lake Michigan,,